U.S. patent number 7,874,666 [Application Number 12/055,868] was granted by the patent office on 2011-01-25 for smart sunglasses, helmet faceshields and goggles based on electrochromic polymers.
This patent grant is currently assigned to University of Washington through its Center for Commercialization. Invention is credited to Chao Ma, Minoru Taya, Chunye Xu.
United States Patent |
7,874,666 |
Xu , et al. |
January 25, 2011 |
Smart sunglasses, helmet faceshields and goggles based on
electrochromic polymers
Abstract
Eyewear exhibiting a variable light transmittance functionality
is achieved by including a smart lens incorporating an
electrochromic (EC) polymer, switchable between a first state and a
second state in response to a voltage selectively applied thereto.
The smart eyewear includes the smart lens, a voltage source, and a
support. The EC polymer transmits more light in the first state
than in the second state, because changing the state of the EC
polymer varies the light transmittance of the smart lens. The
voltage source is configured to provide the voltage required to
switch the EC polymer between the first state and the second state,
while the support member is configured to support the smart lens
and enable a user to wear the smart eyewear. Embodiments can
include sensors and controllers to automate the switching, as well
as energy harvesting elements to increase battery life.
Inventors: |
Xu; Chunye (Seattle, WA),
Ma; Chao (Seattle, WA), Taya; Minoru (Mercer Island,
WA) |
Assignee: |
University of Washington through
its Center for Commercialization (Seattle, WA)
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Family
ID: |
39789017 |
Appl.
No.: |
12/055,868 |
Filed: |
March 26, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080239452 A1 |
Oct 2, 2008 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60908102 |
Mar 26, 2007 |
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Current U.S.
Class: |
351/44; 351/158;
2/15; 359/652 |
Current CPC
Class: |
G02C
7/101 (20130101) |
Current International
Class: |
G02C
7/10 (20060101) |
Field of
Search: |
;351/41,44,158
;349/13,14 ;359/265 ;2/15,426-434 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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62265630 |
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Nov 1987 |
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JP |
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WO 92/10130 |
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Jun 1992 |
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WO |
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WO 03/001290 |
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Jan 2003 |
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WO |
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Other References
Sapp, Shawn A. et al. 1998, "High Contrast Ratio and Fast-Switching
Dual Polymer Electrochromic Devices." Chem. Mater. 10: 2101-2108.
cited by other .
Schwenderman, Irina et al. 2001. "Combined Visible and Infrared
Electrochromism Using Dual Polymer Devices." Advanced Materials
13:9 634-637. cited by other .
Welsh, Dean M. et al. 1999. "Enhanced Contrast Ratios and Rapid
Switching in Electrochromics Based on Poly
(3,4-propylenediozythiophene) Derivitives." Advanced Materials
11:16 1379-1382. cited by other .
Xu et al., "Enhanced Contrast Ratios and Rapid Switching Color
Changeable Devices Based on Poly(3,4-Propylenedioxythiophene)
Derivative and Counterelectrode", Proc. SPIE, vol. 4695; 2002; pp.
442-450. cited by other.
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Primary Examiner: Mai; Huy K
Parent Case Text
RELATED APPLICATIONS
This application is based on a prior provisional application Ser.
No. 60/908,102, filed on Mar. 26, 2007, the benefit of the filing
date of which is hereby claimed under 35 U.S.C. .sctn.119(e).
Claims
The invention in which an exclusive right is claimed is defined by
the following:
1. Smart eyewear exhibiting variable light transmittance
functionality, comprising: (a) a smart lens member including an
electrochromic (EC) polymer, the EC polymer being switchable
between a first state and a second state by selectively applying a
voltage thereto, wherein the EC polymer transmits more light in the
first state than in the second state; (b) a voltage source member
that is selectively connectable to the smart lens and is configured
to provide the voltage required to switch the EC polymer between
the first state and the second state; (c) a controller configured
to control the state of the EC polymer, the controller being
operatively coupled to the smart lens member and the voltage source
member; (d) a support member configured to support the lens and
enable a user to wear the smart eyewear, the support member
comprising a first earpiece and a second earpiece, the controller
being incorporated into at least one of the first earpiece and the
second earpiece such that the controller is not readily visible;
and (e) an energy harvesting element configured to enable energy
from a user of the smart eyewear to provide the voltage required to
switch the EC polymer between the first state and the second state,
wherein the energy harvesting element meets at least one condition
selected from a group of conditions consisting of: (i) a first
condition wherein the energy harvesting element converts heat
energy from a user of the smart eyewear to electrical energy; and
(ii) a second condition wherein the energy harvesting element
produces electrical energy when there is a difference of more than
about two degrees Celsius between a body of the user and an ambient
environment.
2. The smart eyewear of claim 1, wherein the voltage source member
comprises a battery electrically coupled to the smart lens
member.
3. The smart eyewear of claim 1, further comprising a user
interface configured to enable a user to selectively switch the EC
polymer between the first state and the second state.
4. The smart eyewear of claim 3, wherein the user interface is a
touch sensor that is activated by being touched.
5. The smart eyewear of claim 3, wherein the user interface enables
the voltage to be selectively varied, to selectively vary a
transmittance of the EC polymer in the second state.
6. The smart eyewear of claim 1, further comprising a microphone
operatively coupled to the controller, such that the controller is
configured to automatically switch the EC polymer between the first
state and the second state based on a signal provided by the
microphone corresponding to an audible command.
7. The smart eyewear of claim 1, wherein the EC polymer in the
smart lens member is configured as a plurality of individually
addressable pixels arranged in a grid format, each pixel being
switchable between a transparent state and non-transparent state by
selectively applying a voltage thereto.
8. The smart eyewear of claim 7, wherein the controller is
operatively coupled to each pixel, and the plurality of
individually addressable pixels are implemented using different EC
polymers, enabling at least one of a tint and a color associated
with the smart lens member to be selectively varied by switching
the plurality of individually addressable pixels with an applied
voltage.
9. The smart eyewear of claim 7, wherein the controller is
operatively coupled to each pixel, and the controller is configured
to selectively actuate pixels disposed proximate an upper portion
of the lens.
10. The smart eyewear of claim 1, wherein the smart lens member
comprises a laminated EC structure having a cathodic EC polymer
layer and no anodic EC polymer layer.
11. The smart eyewear of claim 1, wherein the EC polymer in the
smart lens member is disposed in an upper portion of the smart lens
member.
12. The smart eyewear of claim 1, further comprising an additional
smart lens member.
13. The smart eyewear of claim 1, wherein the EC polymer in the
smart lens member comprises a first EC polymer disposed in an upper
portion of the smart lens member, and a second EC polymer disposed
in a lower, portion of the smart lens member, such that a
transmittance of each of the upper and lower portions of the smart
lens member can be individually controlled.
14. The smart eyewear of claim 1, wherein the smart lens member
comprises a laminated structure, the laminated structure comprising
the EC polymer and further including: (a) a first substantially
transparent electrode; (b) a substantially transparent gel
electrolyte, such that the EC polymer is disposed between the first
substantially transparent electrode and the substantially
transparent gel electrolyte; (c) an ion storage layer; and (d) a
second substantially transparent electrode, such that the ion
storage layer is disposed between the second substantially
transparent electrode and the substantially transparent gel
electrolyte.
15. The smart eyewear of claim 14, wherein at least one of the
first substantially transparent electrode and the second
substantially transparent electrode comprises a flange that extends
beyond an edge of the laminated structure, each flange being
configured to facilitate coupling the laminated structure to the
support member.
16. The smart eyewear of claim 14, wherein the ion storage layer
comprises a vanadium pentoxide film.
17. The smart eyewear of claim 16, wherein the vanadium pentoxide
film exhibits a green tint, such that even when the EC polymer is
in the first state, a transmittance of the smart lens member is
reduced due to the green tint.
18. The smart eyewear of claim 14, wherein the second substantially
transparent electrode is covered by an anti-ultra-violet layer
configured to reduce an intensity of ultra-violet radiation
entering the laminated structure.
19. The smart eyewear of claim 14, wherein the EC polymer and the
ion storage layer are conditioned by exposure to the gel
electrolyte prior to assembly.
20. The smart eyewear of claim 1, wherein the smart lens member is
incorporated into an optical blank used for prescription
eyewear.
21. Smart eyewear exhibiting a variable light transmittance
functionality, comprising: (a) a smart lens member including at
least one electrochromic (EC) polymer, each EC polymer being
switchable between a first state and a second state by selectively
applying a voltage thereto, wherein the EC polymer transmits more
light in the first state than in the second state; (b) a voltage
source for providing the voltage required to switch each EC polymer
between the first state and the second state; (c) a support member
configured to support the lens and enable a user to wear the smart
eyewear, and (d) an energy harvesting element configured to enable
energy from a user of the smart eyewear to provide the voltage
required to switch the EC polymer between the first state and the
second state, wherein the energy harvesting element meets at least
one condition selected from a group of conditions consisting of:
(i) a first condition wherein the energy harvesting element
converts heat energy from a user of the smart eyewear to electrical
energy; and (ii) a second condition wherein the energy harvesting
element produces electrical energy when there is a difference of
more than about two degrees Celsius between a body of the user and
an ambient environment.
22. The smart eyewear of claim 21, wherein the smart eyewear is
implemented using a form factor selected from a group consisting
of: (a) a helmet in which the smart lens member functions as a face
shield; (b) a helmet in which the smart lens member functions as an
eye shield; (c) a pair of sunglasses; (d) a sports goggle; (e) a
ski goggle; and (f) a pair of safety glasses.
23. The smart eyewear of claim 21, further comprising a smart lens
exhibiting a variable light transmittance functionality, wherein
the smart lens comprises a laminated structure, the laminated
structure including: (a) a first substantially transparent
electrode; (b) at least a portion of the (EC) polymer, the portion
of the EC polymer being switchable between the first state and the
second state by selectively applying the voltage required to switch
each EC polymer thereto, wherein the portion of the EC polymer
transmits more light in the first state than in the second state;
(c) a substantially transparent gel electrolyte, such that the
portion of the EC polymer is disposed between the first
substantially transparent electrode and the substantially
transparent gel electrolyte; (d) an ion storage layer; (e) a second
substantially transparent electrode, such that the ion storage
layer is disposed between the second substantially transparent
electrode and the substantially transparent gel electrolyte; and
(f) conductors used to couple the smart lens to the voltage source,
wherein at least one of the first substantially transparent
electrode and the second substantially transparent electrode
comprises a flange that extends beyond an edge of the laminated
structure, each flange being configured to facilitate coupling the
laminated structure to the support member.
Description
BACKGROUND
Sunglasses are popular as fashion items, but are also used to
protect the wearer's eyes from harmful effects of sunlight, such as
cataracts, macular degeneration, and photokeratitis. Traditional
materials used to make lenses for sunglasses include plastic
(polycarbonate and CR-39 resins) and crown glass. Such lenses are
generally tinted to reduce the transmittance of the lens, or
include a polarized layer that reduces light intensity by about 50%
and can reduce the glare of reflected light. Typically, the lenses
of sunglasses are invariant, in that such lenses exhibit only one
fixed color state, and their transparency is not variable (other
than in regard to the polarization angle of the light relative to
the lens polarization axes--if polarized lenses are used). During
outdoor activities such as motorcycling and skiing, sunlight
conditions can vary considerably, and invariant conventional lenses
cannot adjust to such varying conditions of brightness in the
ambient light.
Photochromic lenses were developed to address this issue.
Photochromic lenses incorporate light sensitive molecules into the
lens (or into a film applied to the lens). Such light sensitive
molecules cause the lenses to become less transparent when exposed
to ultra-violet (UV) radiation. Once the UV component of the
ambient light is substantially reduced (for example, by walking
indoors), the lenses gradually return to their clear state.
Photochromic glass lenses generally incorporate silver halides into
the lens, while polymer photochromic lenses employ organic
molecules, such as oxazines and napthopyrans.
Typically, photochromic lenses darken substantially in response to
UV light in less than one minute, and then continue to darken very
slightly over the next fifteen minutes. As soon as exposure to the
UV light ceases, the lenses begin to clear, becoming noticeably
less tinted within two minutes, and are generally transparent
within five minutes. However, it normally takes more than fifteen
minutes for the lenses to become completely transparent.
In addition to the relatively slow response time of these passive
photochromic lenses, such lenses exhibit temperature dependency,
which prevents such lenses from achieving the darker tints in hot
weather that they do when exposed to milder weather. In contrast,
photochromic lenses achieve deep tints when exposed to cold weather
conditions. Thus, photochromic lenses are more suitable for snow
skiers than beachgoers. The temperature dependency also increases
the time required for tinted lenses to return to their transparent
state after exposure of the lenses to UV radiation has been
terminated.
Yet another limiting factor for photochromic lenses is that they
respond only to UV radiation, and not visible light. Because most
vehicle windows act as a UV filter, photochromic lenses will not be
exposed to much UV radiation when worn in a car, and thus, will not
achieve the deeper tints for blocking light desired for sunglasses
in bright environments.
In contrast, smart color change materials (as opposed to the
passive photochromic materials discussed above) are characterized
by their ability to vary their transparency (i.e., their
transmittance values) upon application of an electric potential
across the materials. Smart color change materials include
suspended particles, liquid crystals, and electrochromics.
Suspended particle devices (SPD) and liquid crystal devices (LCD)
are capable of rapid switching, and do not suffer from the UV and
temperature dependencies of passive photochromic materials.
However, SPDs and LCDs require high voltages be applied to control
light transmittance. Further, they are characterized by relatively
high production costs, complex manufacturing requirements, lack of
memory function, and limited color availability that has prevented
them from being used in smart sunglasses and goggles.
Electrochromic (EC) materials can change their color when an
electrical potential is applied, due to electrochemical oxidation
and reduction reactions occurring within the materials. However, EC
materials based on inorganic transition metal oxides (such as
WO.sub.3) have relatively slow response times (on the order of tens
of seconds), and relatively high processing costs.
EC polymers are more promising materials for use in sunglasses. EC
polymer based devices (ECDs) exhibit several desirable
characteristics. They require power only during switching state;
their operating voltages and energy consumption are low; they have
rapid response times; they exhibit an open circuit memory function;
they exhibit great repeatability; they offer rich color choices;
and they are relatively easy to manufacture. Based on these
characteristics, it clearly would be desirable to provide smart
eyewear incorporating EC polymers having these advantages.
SUMMARY
A first aspect of the concepts disclosed herein is an EC polymer
based smart eyewear exhibiting a variable light transmittance
functionality. The smart eyewear includes a smart lens member, a
voltage source member, and a support member. The smart lens member
includes an EC polymer switchable between a first state and a
second state, by selectively applying a voltage thereto.
Significantly, the EC polymer transmits a larger amount of light in
the first state than in the second state, thus, changing the state
of the EC polymer varies the light transmittance of the smart lens.
The voltage source member is configured to provide the voltage
required to switch the EC polymer between the first state and the
second state, while the support member is configured to support the
smart lens and enable a user to wear the smart eyewear. In at least
some exemplary embodiments, the voltage source member comprises a
portable battery that is electrically coupled to the smart lens
member, although if the smart eyewear is intended to be used
primarily in a fixed location, such as a vehicle, then a power
source in the vehicle could be used to provide the voltage.
In at least one exemplary embodiment, the smart eyewear further
includes a user interface configured to enable a user to
selectively switch the EC polymer between the first state and the
second state. (As discussed in greater detail below, a sensor can
be incorporated into the smart eyewear to trigger the EC polymer so
that it switches between states automatically, optionally
eliminating the need for a user interface.) In an exemplary (but
not limiting) embodiment including a user interface, the user
interface comprises a touch sensor switch. Alternatively, a rocker
switch or rotary dial can be employed to control the state of the
EC polymer. Those of ordinary skill in the art will recognize that
many different types of user-actuatable switches can be employed
for this purpose. Where the EC polymer exhibits different
transmittance properties in the second state, dependent upon the
applied voltage, the user interface can enable the voltage to be
selectively varied, to selectively vary the transmittance of the EC
polymer over a desired range between the first state and the second
state.
In another exemplary, but not limiting embodiment, the smart
eyewear further includes a controller configured to control the
state of the EC polymer. For example, the controller can be
operatively coupled to the smart lens member and the voltage source
member. In at least one embodiment, the controller is integrated
into the support member, such that the controller is not readily
visible. Yet another exemplary embodiment includes a light sensor
operatively coupled to the controller, such that the controller is
configured to automatically switch the EC polymer between the first
state and the second state based on a signal provided by the light
sensor (for example, when the sensor detects light levels exceeding
a predetermined threshold value), or the controller can vary the
voltage applied to the EC polymer to selectively vary its
transmittance as a function of the brightness levels of light
incident on the light sensor. In still another exemplary
embodiment, the smart eyewear includes a microphone operatively
coupled to the controller, such that the controller is configured
to automatically switch the EC polymer between the first state and
the second state based on a signal provided by the microphone (for
example, the smart eyewear can be voice activated to respond to a
spoken command to change the transmittance level of the EC
polymer).
In another exemplary, but not limiting embodiment, the EC polymer
in the smart lens member is configured as a plurality of
individually addressable pixels arranged in a grid format over the
smart lens member, with each pixel being switchable between a
transparent state and non-transparent state, by selectively
applying a voltage thereto. For example, the controller can be
operatively coupled to each pixel, and the plurality of
individually addressable pixels can be implemented using different
color EC polymers, enabling either one or both of a tint and a
color associated with the smart lens member to be selectively
varied by manipulating the plurality of individually addressable
pixels. In another example, the controller is operatively coupled
to each pixel, and the controller is configured or programmed to
selectively actuate pixels disposed proximate on a specific portion
(e.g., on an upper portion) of the lens, such that the smart lens
member transmits less light at that area.
In still another exemplary, but not limiting embodiment, the smart
eyewear further includes an energy harvesting element comprising
the voltage source and configured to enable energy harvested from a
user of the smart eyewear to provide the voltage required to switch
the EC polymer between the first state and the second state. In at
least some embodiments, the energy harvesting element is
operatively coupled to a rechargeable battery, which comprises the
voltage source. Exemplary energy harvesting elements include, but
are not limited to, devices that convert heat energy produced by
the body of a user of the smart eyewear into electrical energy.
Such devices can be based on junctions formed of dissimilar metals
or semiconductors, can produce electrical energy when there is a
difference of more than about two degrees Celsius between the
user's body and the ambient environment, and can be integrated into
the support member.
In at least one embodiment, the EC polymer in the smart lens member
is disposed only in an upper portion of the smart lens member, such
that when the EC polymer is in the second state, the smart lens
member transmits less light at that area. In a related embodiment,
the EC polymer in the smart lens member includes a first EC polymer
disposed in an upper portion of the smart lens member, and a second
EC polymer disposed in a lower portion of the smart lens member,
such that a transmittance of the upper and lower portions of the
smart lens member can be individually and separately
controlled.
The smart eyewear can employ a single smart lens member when the
smart eyewear is implemented as a face shield of a helmet, or used
in glasses or goggles including only a single large lens covering
both eyes. In other exemplary embodiments, the smart eyewear
includes an additional smart lens member, as in conventional
eyeglasses and sunglasses that include pairs of lenses--one lens
for each eye of the user.
In at least one exemplary embodiment, the smart lens member
comprises a laminated EC device structure having a cathodic EC
polymer layer and no anodic EC polymer layer.
In at least another exemplary embodiment, the smart lens member
comprises a laminated structure including the EC polymer, wherein
the laminated structure includes a substantially transparent
electrode substrate, a substantially transparent gel electrolyte
(such that the EC polymer is disposed between the substantially
transparent electrode substrate and the substantially transparent
gel electrolyte), an ion storage layer, and a substantially
transparent electrode upper layer (such that the ion storage layer
is disposed between the substantially transparent electrode upper
layer and the substantially transparent gel electrolyte). In at
least one related exemplary embodiment, at least one of the
substantially transparent electrode upper layer and the
substantially transparent electrode substrate comprises a flange
that extends beyond an edge of the laminated structure, the flange
being configured to facilitate coupling the laminated structure to
the support member. In at least another exemplary embodiment, the
ion storage layer comprises a vanadium pentoxide film (thus,
collectively, the ion storage layer and the substantially
transparent electrode upper layer function as a counter-electrode).
In at least one exemplary embodiment, the vanadium pentoxide film
exhibits a green tint, such that even when the EC polymer is in the
first state, a transmittance of the smart lens member is reduced
due to the green tint. In another exemplary embodiment, the
substantially transparent electrode upper layer is covered by an
anti-UV layer configured to reduce an amount of UV radiation
entering the laminated structure.
Yet another aspect of the concepts disclosed herein encompasses
smart eyewear exhibiting a variable light transmittance
functionality, where the smart eyewear includes a smart lens member
including at least one EC polymer, each EC polymer being switchable
between a first state and a second state by selectively applying a
voltage thereto (wherein the EC polymer transmits a larger amount
of light in the first state than in the second state), a voltage
source for providing the voltage required to switch each EC polymer
between the first state and the second state, and a support member
configured to support the lens and enable a user to wear the smart
eyewear. The voltage source can comprise disposable batteries, or
rechargeable batteries, and may use conductors to convey voltage
from the voltage source to the smart lens member. In addition, the
voltage source may comprise energy harvesting elements, may be
integrated into the smart eyewear, or external to the smart
eyewear, and may employ permutations and combinations of each of
the alternatives.
Still another aspect of the concepts disclosed herein encompasses a
smart lens exhibiting a variable light transmittance functionality,
including: (1) a substantially transparent electrode substrate; (2)
an EC polymer, the EC polymer being switchable between a first
state and a second state by selectively applying a voltage thereto,
so that the EC polymer transmits more light in the first state than
in the second state; (3) a substantially transparent gel
electrolyte disposed between the substantially transparent
electrode substrate and the substantially transparent gel
electrolyte; (4) an ion storage layer; (5) a substantially
transparent electrode upper layer disposed between the
substantially transparent electrode upper layer and the
substantially transparent gel electrolyte; and, (6) electrical
conductors that couple the smart lens to a voltage source. The
electrical conductors may comprise flexible electrical conductors,
electrically conductive adhesives, wire-based electrical
conductors, conductive flanges extending outwardly from the
laminated structure, and permutations and combinations thereof.
This Summary has been provided to introduce a few concepts in a
simplified form that are further described in detail below in the
Description. However, this Summary is not intended to identify key
or essential features of the claimed subject matter, nor is it
intended to be used as an aid in determining the scope of the
claimed subject matter.
DRAWINGS
Various aspects and attendant advantages of one or more exemplary
embodiments and modifications thereto will become more readily
appreciated as the same becomes better understood by reference to
the following detailed description, when taken in conjunction with
the accompanying drawings, wherein:
FIG. 1A schematically illustrates a smart lens including an EC
polymer;
FIG. 1B is a side view of the smart lens of FIG. 1A;
FIG. 2 graphically illustrates photo spectrum curves of the smart
lens of FIG. 1A between 380 nm and 800 nm, for both the transparent
state and the colored state;
FIG. 3A graphically illustrates photo spectrum curves of the smart
lens of FIG. 1A between 380 nm and 800 nm, illustrating its
response to an applied potential varying from about 0.2 V to about
1.4 V;
FIG. 3B graphically illustrates transmittance of the smart lens of
FIG. 1A at 580 nm, in response to an applied potential ranging from
about 0.2 V to about 1.4 V;
FIG. 4 graphically illustrates a response time curve for the smart
lens of FIG. 1A, in response to an applied potential of .+-.1.2
VDC;
FIG. 5A is an image of a prototype of a pair of smart sunglasses
incorporating the smart lens of FIG. 1A, where the EC polymer in
the smart lens is in a first state (i.e., is generally
transparent);
FIG. 5B is an image of the prototype of the pair of smart
sunglasses incorporating the smart lens of FIG. 1A, where the EC
polymer in the smart lens is in a second state (i.e., is generally
opaque);
FIG. 6 is a block diagram showing the basic elements of the novel
smart eyewear disclosed herein;
FIG. 7 is a block diagram of an exemplary embodiment of smart
eyewear including a controller;
FIG. 8 is a block diagram of an exemplary embodiment of smart
eyewear including a sensor and a controller configured to
automatically control switching of the smart lens between a first
state and a second state;
FIG. 9 is a block diagram of an exemplary embodiment of smart
eyewear including an energy harvesting member that derives energy
from the user's body (or the temperature differential between
ambient and that of the user's body);
FIG. 10 is a block diagram of an embodiment of smart eyewear
including a pixelated smart lens;
FIGS. 11 and 12 schematically illustrate a pair of smart glasses
100, which as shown incorporate a plurality of the elements
disclosed with respect to FIGS. 6-10;
FIG. 13 schematically illustrates a pair of smart glasses 102,
which as shown incorporates a plurality of the elements disclosed
with respect to FIGS. 6-10;
FIG. 14 schematically illustrates a smart helmet 110 being worn by
a user;
FIG. 15 schematically illustrates a pair of smart goggles 120 being
worn by a user; and
FIGS. 16A and 16B schematically illustrate incorporating a smart
lens into optical blanks to be used to make prescription
eyewear.
DESCRIPTION
Figures and Disclosed Embodiments are not Limiting
Exemplary embodiments are illustrated in referenced Figures of the
drawings. It is intended that the embodiments and Figures disclosed
herein are to be considered illustrative rather than restrictive.
No limitation on the scope of the technology and of the claims that
follow is to be imputed to the examples shown in the drawings and
discussed herein.
As employed herein and in the claims that follow, the term smart
eyewear is intended to refer to eyewear that can be worn by a user,
where the eyewear exhibits variable light transmittance
functionality, due to the incorporation of an EC polymer
(switchable between a first state and a second state, where a
transmittance of the second state is less that a transmittance in
the first state) into one or more lenses in the eyewear. The term
smart eyewear encompasses (but is not limited to) the following
types of eyewear: sunglasses including a single lens configured to
cover both eyes, sunglasses including two lenses (each lens
intended to cover one eye), goggles including a single lens
configured to cover both eyes, goggles including two lenses (each
lens intended to cover one eye), and face shields (where the face
shield is used as part of a helmet, or used with a support member
to enable the face shield to be worn by a user). The term voltage
source for providing a required voltage to the EC polymer
encompasses, without any implied limitation, disposable batteries,
rechargeable batteries, electrical conductors required to convey
voltage from a voltage source to the EC polymer portion of the
lens, energy harvesting elements that derive electrical power from
the user/ambient environment, voltage sources integrated into the
smart eyewear, voltage sources external to the smart eyewear, and
permutations and combinations thereof. The electrical conductors
used to couple the smart lens to a voltage source encompass
(without any intent to limit) flexible electrical conductors,
electrically conductive adhesives or coatings, wire-based
electrical conductors, foil on a substrate, flanges extending
outwardly from the laminated structure, and permutations and
combinations thereof.
EC polymer materials exhibiting either blue, red, or green colors
have been developed. While a working prototype has been fabricated
using a specific EC polymer,
[3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine]
(PPropOT-Me.sub.2), it should be recognized that use of such an EC
polymer is intended to be exemplary, and not limiting. Furthermore,
while the prototype includes only a single EC polymer, it should be
recognized that the concepts disclosed herein encompass smart
eyewear including more than one type of EC polymer. As noted above,
blue, red, and green EC polymers are known, and at least one
embodiment disclosed herein employs green, red, and blue EC
polymers configured in a pixelated orientation, with each pixel
being individually addressable, to enable a highly versatile smart
eyewear embodiment to be achieved.
The following list of EC polymers can be beneficially employed,
although it should be recognized that the following list is
intended to be exemplary, rather than limiting. Blue in one state,
clear in the second state:
Poly[3-methyl-3'-propyl-3,4-dihydro-2H-thieno(3,4-b)(1,4)dioxepine-
] (PPropOT-MePro). Red in one state, clear in the second state:
Poly[3,3-diethyl-3,4-dihydro-2H,7H-(1,4)dioxepino(2,3-c)pyrrole]
(PPropOP-Et.sub.2). Green in one state, red in the second state: EC
polymer based on
2,5-di-(thien-2-yl)-3,4-di(2,2,2-trifluoroethoxy)-thiopene. Green
in one state, purple in the second state: EC polymer based on
2,5-(2,3-dihydro-thieno[3,4][1,4]dioxin-5-yl)-3,4-di(2,2,2-trifluoroethox-
y)-thiopene. Green in one state, clear in the second state: EC
polymer based on
2,3-dibenzyl-5,7-di(thien-2-yl)-thieno-[3,4]-pyrazine.
In the working prototype, the PPropOT-Me.sub.2 EC film exhibits
desirable properties, such as a high transmittance contrast ratio
(.DELTA.% T) between a blue color (the second state) and a
transparent state (the first state), low operation voltage
potentials required to switch between the first and second states,
high conductivity, and high thermal stability.
One exemplary smart lens 10 for the smart eyewear disclosed herein
is a multilayered (i.e., laminated) EC device, schematically
illustrated in FIG. 1A and FIG. 1B (while these Figures illustrate
a left lens, it should be recognized that the same structure can be
used to create a right lens, the right lens being a mirror image of
the left lens). The EC working layer, a PPropOT-Me.sub.2 film 12,
is deposited on an Indium Tin oxide (ITO) coated glass substrate
14. The counter electrode layer of this embodiment is a vanadium
oxide (V.sub.2O.sub.5) film 16, also deposited on ITO coated glass
substrate 18. The V.sub.2O.sub.5 film serves as an ion storage
layer and works with the PPropOT-Me.sub.2 film as a pair. When used
in combination with an electrolyte layer including lithium
perchlorate, the EC film is reduced with an applied potential and
changes color to blue, the V.sub.2O.sub.5 film will simultaneously
absorb ClO.sub.4.sup.- ions (provided by a gel electrolyte layer
20). When the EC film is oxidized with an opposite potential and
changes to the transparent state, the V.sub.2O.sub.5 film will
absorb Li.sup.+ ions (also provided by a gel electrolyte layer 20).
During switching, the V.sub.2O.sub.5 film maintains a light green
color (thus, even when the EC polymer is in the first transparent
state, the transmittance of the lens will be somewhat reduced, due
to the green tint from the V.sub.2O.sub.5 film). Such a tint is not
problematic for smart eyewear intended to be used in outdoor
daylight environments. Other embodiments can employ a different
counter electrode design, to eliminate such tinting, if no
reduction in the transmittance of the lens is desired when the EC
polymer is in the transparent state. If the slight tint due to the
V.sub.2O.sub.5 film is considered undesirable, other types of
counter-electrode materials can be investigated. For example,
composites materials including V.sub.2O.sub.5 and another metal
oxide, such as TiO.sub.2, should provide the charge balancing
functionality with a less noticeable tint. Those of ordinary skill
in the art will recognize that many other metal oxides are known
that can be tested for their charge balancing and optical clarity
properties.
It should also be noted that the saturation of the tint due to the
V.sub.2O.sub.5 film is a function of the relative thickness of the
V.sub.2O.sub.5 film. The thinner the V.sub.2O.sub.5 film, the less
noticeable will be the tint. The function of the V.sub.2O.sub.5
layer is to maintain a proper charge balance during operation of
the smart lens. The V.sub.2O.sub.5 layer need only be as thick as
is required to achieve a charge capacity that is equal to or larger
than the charge capacity of the EC polymer film layer.
Transparent polymer gel electrolyte layer 20 is a good conductor
for small ions such as ClO.sub.4.sup.- and Li.sup.+ while being an
insulator for electrons, and is sandwiched between the working
electrode layer (i.e., the EC polymer film and the ITO substrate)
and the counter electrode layer (i.e., V.sub.2O.sub.5 film and the
ITO substrate). Gel electrolyte layer 20 is an ion transport layer
and ions move quickly through that layer during switching. It may
be desirable (although not required) to add a transparent anti
ultra-violet (UV) layer 22 to protect the user's eyes from harmful
UV rays. This layer also prevents organic materials (such as the EC
polymer) from breaking down due to exposure to UV radiation.
During deposition of the EC polymer layer onto the ITO substrate,
the electric potential drop caused by the surface resistance of ITO
glass can cause the EC film to deposit non-uniformly. This issue
can be addressed by using relatively low sheet resistance ITO glass
and a copper tape electrode coupled to one or more edges of the ITO
glass. The copper tape electrode can then be removed, or the ITO
glass with the EC polymer film can be reshaped to remove the copper
electrode, such that the electrode is not part of the resulting
laminated structure.
Note that ITO substrate 14 includes a flange 24, and ITO substrate
18 includes a flange 26. These flanges can be used to electrically
couple the layered EC device to a voltage source, and/or to attach
the lens structure to a support member, where the support member is
configured to enable the user to wear the smart eyewear. Flanges 24
and 26 are particularly well suited for coupling the laminated lens
structure to the frame of a pair of sunglasses. It must be
recognized that such flanges are intended to be exemplary, rather
than limiting. For example, conductors 28 and 30 (such as wires or
flexible conductive tapes or foil, as shown in FIG. 1B) can be
embedded in the layered EC structure, to facilitate coupling the
layered EC structure to a voltage source. If employed, conductor 28
electrically couples the working electrode (i.e., the EC polymer
film and the ITO substrate) to the voltage source, and conductor 30
electrically couples to the counter electrode (i.e., V.sub.2O.sub.5
film and the ITO substrate) to the voltage source. It should also
be recognized that the flanges are not required to mount a smart
lens to a support, in that holes can be drilled through the smart
lens, and non conductive fasteners can be used to attach the smart
lens to a support member, or the smart lens can be sized and shaped
to achieve an interference fit with a support member (as is
commonly employed to attach eye glass lenses to an eye glass
frame).
The EC material, PPropOT-Me.sub.2 monomer was synthesized via a
procedure described in described in U.S. Pat. No. 7,038,828. All
materials were purchased from Sigma-Aldrich Corporation (St. Louis,
Mo.), except Tetra-n-butyl ammonium perchlorate (TBAP,
electrochemical grade) and Lithium perchlorate (99% anhydrous,
packed under argon), which were purchased from Alfa Aesar (Ward
Hill, Mass.). Because the EC film being fabricated is sensitive to
moisture and air, which affects the performance of the resulting
laminated EC device, all the materials were dried before use and
stored in a sealed container (i.e., a glove box) filled with
argon.
The gel electrolyte was based on poly(methylmethacrylate) (PMMA)
and lithium perchlorate (LiClO.sub.4) and was plasticized using
propylene carbonate (PC) and ethylene carbonate (EC), to form a
highly transparent and conductive gel. It should be recognized that
this specific gel electrolyte is intended to be exemplary, rather
than limiting, and other electrolytes can be employed (including
liquid electrolytes, although the use of gel electrolytes
simplifies fabrication of the smart lens).
The EC film was deposited on the ITO substrate from a solution
including 0.01 M of the monomer and 0.1 M of
LiClO.sub.4/Acetonitrile (ACN). Electrochemical deposition of the
film was carried out by using an electrochemical analyzer (CHI
605A, CH Instruments), utilizing the chronoamperometry method. A
three-electrode cell (with a silver wire as a reference electrode,
an ITO glass (Thin Film Device) as a working electrode, and a
platinum plate as a counter electrode) was used for
electro-polymerizing the polymer film.
The vanadium pentoxide (V.sub.2O.sub.5) film was deposited on the
ITO glass substrate by the chronoamperometry method in a
V.sub.2O.sub.5.nH.sub.2O sol-gel solution. These gels were
synthesized using conventional techniques.
After depositing the EC polymer film onto ITO substrate 14, and
depositing the V.sub.2O.sub.5 film onto ITO substrate 18, both
film/substrate combinations (i.e., the working electrode and the
counter-electrode) were placed into a 0.1 M LiClO.sub.4/PC
electrolyte solution and were electrochemically conditioned (via
chronocoulometry), in order to ensure that the inorganic ions in
the films were compatible with the LiClO.sub.4/PC environment
provided by gel electrolyte layer 20. Of course, if a different gel
electrolyte is employed, a corresponding different electrolyte
solution would likely be employed for this step. It should be noted
that rather than using a glass substrate, polymers could be used
instead (such that the indium tin oxide layer is deposited on the
polymer, as opposed to glass). The use of polymeric substrates
rather than glass substrates may facilitate production of a curved
smart lens, as opposed to a flat smart lens. Consumers are likely
to consider curved smart lenses to be more fashionable, because
curved lenses facilitate a wider choice of eyewear designs.
After conditioning both film/substrate combinations (i.e., the
working electrode and the counter-electrode), the EC film coated
ITO glass surface (i.e., the working electrode) was entirely
covered with a uniform thin layer of the selected gel electrolyte.
The V.sub.2O.sub.5 film coated ITO glass (i.e., the
counter-electrode) was then placed on top of the working electrode,
and the working electrode and the counter-electrode (with the gel
electrolyte disposed between them) were clamped together. A UV
curing epoxy (OG112-4, Epoxy Technology, Billerica, Mass.) was used
as a hermetic barrier to seal the laminated EC device (i.e., the
smart lens). The assembly process was performed in a glove box
filled with argon, to eliminate quality degradation associated with
exposure of the films to moisture and air (i.e., oxygen).
After assembly of the smart lens prototype, the optical performance
(transmittance) of smart lens 10 was characterized on a
spectrophotometer (a model V-570.TM. available from Jasco; Easton,
Md.). FIG. 2 graphically illustrates the photo spectrum curves of
smart lens 10 at wavelengths from about 380 nm to 800 nm. A voltage
potential of 1.2 VDC was applied in a selected polarity, to achieve
either a colored or transparent state. At a wavelength for incident
light of about 580 nm, the transmittance (% T) of the smart lens is
about 45% in the transparent state (i.e., the first state), and
about 5% in the colored state (i.e., the second state).
The spectrum data indicates that smart lens 10 changes its optical
performance (in terms of its transmittance) as a function of the
applied voltage potential. Significantly, the transmittance of
light in the colored state can be adjusted by varying the voltage
potential applied. The photo spectrum curves for different applied
voltage potentials are graphically illustrated in FIG. 3A and FIG.
3B. Before each applied voltage, a 1.2 VDC potential was applied to
the smart lens, in order to make it transparent (i.e., to
transition the EC polymer film to the first state), and then an
opposite potential varying from 0.2-1.4 VDC was applied for 1
second to color the lens (i.e., to transition the EC polymer film
to the second state). The transmittance of the smart lens decreases
as the applied voltage is increased, but the rate of change in
transmittance gradually decreases as the potential is increased.
After about 1.2 VDC, the spectrum curves are substantially
similar.
During outdoor activities, sunglasses and goggles require a short
response time in order to adapt to various rapidly changing
environmental conditions. Therefore, the color changing response
time of the smart lens was characterized and is graphically
illustrated in FIG. 4. With .+-.1.2 VDC potential applied, the
smart lens transitions to a fully saturated colored state (i.e., to
the second state) in 1 second and, to a fully transparent state
(i.e., the first state) in 2 seconds. This response time is much
shorter than the response time exhibited by inorganic EC materials
and is sufficiently fast to adjust to varying ambient lighting
conditions found when hiking, skiing, or motorcycling (where such
activities are intended to be exemplary, rather than limiting).
Significantly, not only is the driving voltage required to change
the state of the smart lens relatively low, but the amount of
electric charge needed to switch the optical state of the EC
polymer is also relatively small. In other words, the energy
consumption during switching is low. The electric charge
consumption of right and left lenses (based on smart lens 10 of
FIGS. 1A and 1B) was empirically measured. When switching the smart
lens from the fully transparent state (i.e., the first state) to a
fully colored state (i.e., the second state), the electric charge
required was less than 0.02 Coulombs. Thus, the smart lens can be
powered by commercially available button cell batteries (i.e., of
the type generally used in watches, calculators, and hearing aids),
whose standard electric capacity is around 100 Coulombs. A
prototype of a pair of smart sunglasses, described in greater
detail below, was powered by a single button cell battery with 1.55
VDC potential (e.g., an Energizer type EPX 76.TM. battery). The
switching time between states in this prototype was about 2
seconds.
FIGS. 5A and 5B are images of the prototype pair of smart
sunglasses noted above, fabricated using the smart lenses described
above. Right and left smart lenses are adhesively coupled to a pair
of plastic safety glasses 42. Copper tape 34 is used to couple
flanges 16 of the right and left lenses to conductive wires 38.
Similarly, copper tape 40 is used to couple flanges 18 of the right
and left lenses to conductive wires 38, which are coupled to a
button cell battery 36 and an on/off switch 32.
While other EC polymers can be employed, it is significant to note
that PPropOT-Me.sub.2 film based EC devices have long lifetimes and
an open circuit memory function. After over 100,000 cycles of
switching between the fully colored and fully transparent state,
the prototype device of FIGS. 5A and 5B showed only a 6% change in
transmittance. Furthermore, the prototype device was maintained in
both the colored state and the transparent state without electric
charge for 30 days. During that period, the transmittance at 580 nm
changed less than 6% in the fully colored state. There was even
less change in the transmittance of the transparent state.
In summary, the prototype device shown in FIGS. 5A and 5B was
fabricated using a multi-layer laminated EC structure including a
cathodic EC polymer film (PPropOT-Me.sub.2) working electrode and a
V.sub.2O.sub.5 film counter electrode (where both film layers were
deposited on ITO glass). The laminated structure also included a
transparent gel electrolyte sandwiched between the two electrodes.
This EC film based device exhibited variable light transmittance
(5%.about.45%), fast response time (1.about.2 seconds), low driving
power (1.2-1.5 VDC) and low energy consumption (less than 0.02
Coulombs per switch). These characteristics indicate that EC
polymer based smart lenses can be beneficially incorporated into
smart eyewear such as smart sunglasses, smart helmets, and smart
goggles.
FIG. 6 schematically illustrates the basic elements of smart
eyewear 50, which includes a support member 52, at least one smart
lens 54, a voltage source 56 operatively coupled to each smart
lens, and a user interface 58 (operatively coupled to the voltage
source, to control the application of a voltage produced by the
voltage source to the smart lens).
The smart lens in FIG. 6, will be generally consistent with the
smart lens disclosed above, although it should be recognized that
many modifications can be made to the smart lens described above,
including the use of different EC polymers, the use of an anodic EC
polymer in place of a cathodic EC polymer, the use of an EC device
including both a cathodic EC polymer and an anodic EC polymer, the
use of different electrolytes, and the use of a different
counter-electrode. Many types of glasses include two lenses (one
for each eye). However, some types of glasses (and many types of
goggles) include a single larger lens that covers both eyes.
Helmets (such as motorcycle helmets and sports helmets) often
employ a single face shield/eye shield. Thus, the concepts
disclosed herein encompass smart eyewear including one or more
smart lenses.
Support member 52 can be implemented as a frame for eyeglasses,
including two elongate arms or earpieces configured to fit over a
user's ears, and a front piece configured to rest on a user's nose
and support one or more lens elements. The elongate arms are
generally hingedly coupled to the earpieces. However, it should be
recognized that the smart eyewear disclosed herein is not limited
to smart glasses, but also encompasses eyewear of other forms,
including helmets and goggles. Thus, support member 52 can also be
implemented in the form of a helmet (such as a motorcycle helmet or
sports helmet for supporting a smart visor or smart eye shield/face
shield, and frames for goggles (which often include a strap
configured to slide behind a user's head to secure the goggles to
the user's face). Support member 52 enables the user to wear the
smart eyewear and also provides support for the smart lens. The
smart lens(es) can be attached to the support member using many
different attachment methods, including but not limited to
fasteners, adhesives, interference fits, hinges, and combinations
thereof.
As noted above, voltage source 56 is used for providing a required
voltage to the EC polymer and can encompass disposable batteries,
rechargeable batteries, one or more capacitors, conductors employed
to convey the voltage from a voltage source to the EC polymer
portion of the lens, energy harvesting elements, voltage sources
integrated into the smart eyewear, voltage sources external of the
smart eyewear, and permutations and combinations thereof.
Disposable batteries will likely be frequently used to implement
voltage source 56. Given the modest power requirements for smart
eyewear, disposable batteries are readily available in compact form
factors, and are convenient and low in cost. Compact batteries
enable portable operation, will add only modest weight to the smart
eyewear, and particularly with eyewear/glasses including
thicker/larger earpieces, can be readily accommodated within the
earpieces of the support member (and even more easily in a helmet
based support member). Rechargeable batteries, and energy
harvesting technologies (discussed in greater detail below) can
also be employed. However, in embodiments where the smart eyewear
will be used in a fixed location (such as in a vehicle or on
motorcycle), instead of using a portable battery (or in addition to
using a portable battery), voltage source 56 can encompass
electrical cords and an interface configured to acquire voltage
from the vehicle's onboard electrical system, or for other
non-movable applications, may comprise a line-voltage operated
power supply.
Many different types of user interfaces are available. A simple
on/off switch can be employed. However, because transmittance of
the EC polymer in the second state is a function of the applied
voltage, a variable switch (such as a potentiometer or rheostat
type switch) can be employed to enable the user to selectively vary
the opacity of the lenses in the smart eyewear by varying the
voltage applied to the EC polymer. For embodiments where style and
fashion are important, invisible or unobtrusive touch activated
switches can be employed. For example, a touch activated switch
could be readily incorporated into one (or both) of the earpieces
in a pair of smart sunglasses, such that the smart lenses can be
actuated by the user simply applying a finger to the touch
activated switch.
Having described the basic concepts of smart lenses and smart
eyewear, further exemplary (but not limiting) embodiments will now
be described. FIG. 7 schematically illustrates smart eyewear 60,
which includes support member 52, at least one smart lens 54,
voltage source 56 operatively coupled to each smart lens, a
controller 62 (operatively coupled to the voltage source), and user
interface 58 (operatively coupled to the controller). The
incorporation of a controller enables the smart eyewear to support
increasingly complicated and/or more versatile functionality. For
example, if user interface 58 is implemented as a touch activated
switch, controller 56 can be configured to implement different
functions based on the number of times user interface 58 is
sequentially actuated or based on the duration of the user
continuously touching the touch activated switch. This approach
will enable the touch actuated switch to not only switch the EC
polymer from the first state to the second state, but also to
selectively vary the voltage supplied, to thereby control the
opacity of the lens in the second state. Furthermore, a single
smart lens might include separately actuable elements (perhaps
implemented using different EC polymers). For example, many types
of lenses (particularly lenses for sunglasses) are more opaque at
the top of the lens than at the bottom. Controller 62 can be
configured to switch the EC polymer at the upper portion of a smart
lens in response to a signal from a first switch, and to switch the
EC polymer at the lower portion of a smart lens in response to a
signal from a second switch (or in response to different inputs
from a single switch), or to vary the opacity of either or both of
the upper and lower portions of the smart lens in response to the
signals from one or more switches. Controller 62 can be implemented
using a microprocessor or an application specific integrated
circuit (ASIC) or as a hard wired logic device or an analog circuit
device, and can be implemented with a form factor sufficiently
small to fit inside a support member (such as a helmet, or an
earpiece of a pair of smart glasses).
FIG. 8 schematically illustrates smart eyewear 64, which includes
support member 52, at least one smart lens 54, voltage source 56
operatively and selectively coupled to each smart lens, user
interface 58, a sensor 66, and a controller 62a (operatively
coupled to the voltage source, the user interface, and the sensor).
The incorporation of the sensor enables the smart eyewear to
automatically respond to input from the sensor, in addition to (or
in place of) input from the user interface. Thus, if desired, the
user interface could be eliminated from this embodiment to make the
operation of the smart eyewear fully automatic. Different types of
sensors can be employed, individually or in combination. For
example, sensor 66 can be implemented using a light sensor
(preferably mounted in the support structure, facing generally
along a line of sight of the user or so that the sensor is exposed
to the same light as the eyes of the user would be if not wearing
the smart eyewear), such that controller 62a is configured to
automatically switch the state of the EC polymer to change the
transmittance of the smart lens based on ambient light conditions.
For example, if the wearer walks into a building after being
outside in bright sunlight, the sensor will detect the reduced
illumination levels, and the controller will automatically cause
the EC polymer in the smart lens to transition from the second
(tinted) state to the first (transparent state). Furthermore,
controller 62a can be configured to vary the applied voltage when
the EC polymer is in the second state, to vary the transmittance of
the smart lens in the second state, so that the transmittance at
moderate light illumination level is only reduced by a moderate
amount. For example, a user may be driving in daylight, but moving
in and out of shadows (due to trees, building or clouds). The
sensor and controller can cooperate to vary the applied voltage, to
increase or decrease the transmittance of the smart lens, based on
ambient light conditions. The threshold light conditions that
trigger a response from the controller can be preset, or in some
embodiments, the user interface can be used to manage the threshold
setting, to enable individual users to adjust the threshold
settings to their particular taste. Another type of sensor that can
be employed is an audio sensor (e.g., a microphone), such that the
user can adjust the smart lens using voice prompts, if a voice
recognition system is included in the controller to recognize
specific commands to control the transmittance level of the smart
lens.
In one exemplary embodiment, a sensor and user interface are
provided, such that the wearer can use the user interface to select
a desired transmittance level for given light conditions, and the
sensor and controller are used to vary the transmittance in
response to changing light conditions, such that the amount of
light reaching the wearer's eyes does not substantially vary even
as the ambient light levels change. For example, a wearer adjusts
the smart eyewear such that a comfortable amount of light reaches
the wearer's eyes during outdoor conditions that are partly cloudy.
When the sensor (disposed to detect ambient light, as opposed to
light reaching a user's eye, recognizing that light reaching a
user's eye may have been reduced in intensity after passing through
the smart lens) detects a decrease in ambient light conditions
(such as the wearer walking into a building), the controller
increases the transmittance of the smart lens (i.e., reduces the
tinting/saturation of the smart lens in the second state, or
switches to the first state, as needed) to compensate for the
reduction in the ambient light. When the sensor detects an increase
in ambient light conditions (such as might be caused by outdoor
conditions moving from cloudy to sunny), the controller decreases
the transmittance of the smart lens (i.e., increases the
tinting/saturation of the smart lens in the second state) to
compensate for the increase in the ambient light. The control can
use known parameters of the smart lens to determine what
transmittance level is required to compensate for the change in the
ambient light conditions (i.e., by using a known relationship or
lookup tables). In a slightly different embodiment, the sensor is
disposed behind the smart lens, such that the sensor is measuring
light intensity as experienced by the wearer, and the controller is
configured to manipulate the transmittance of the smart lens to
ensure that the intensity of light detected by the sensor remains
constant.
FIG. 9 schematically illustrates smart eyewear 68, which includes
support member 52, at least one smart lens 54, a rechargeable
battery 72 operatively coupled to each smart lens, user interface
58, an energy harvesting element 70, and a controller 62b
(operatively coupled to the rechargeable battery, the user
interface, and the energy harvesting element). The incorporation of
the controller enables the smart eyewear to respond to input from
the user interface, and to control recharging of the battery via
the energy harvesting element. The function of the energy
harvesting element is to use the differential between ambient
temperature and that of the user's body to produce electrical
energy, which can be used to recharge the battery (or a capacitor)
and prolong the operational life of the smart eyewear or eliminate
the need for external charging of the battery.
Several types of energy harvesting elements have been employed to
power wristwatches. In some watches, a cam uses kinetic energy from
bodily motion to wind a mainspring, and the mainspring is used to
drive the components of a mechanical watch. In other watches, the
kinetic motion is converted to electricity and stored in a
capacitor. Other energy harvesting technologies convert heat energy
into electricity. While people move their heads frequently, and the
kinetic energy of this head movement could be converted to small
amounts of electrical energy, it is more likely that the heat
converting technology will be preferred, because such technology
can be semiconductor based and does not require the moving parts of
the kinetic energy conversion technology. This technology is
referred to as thermoelectric generation (TEG), which employs
semiconductor elements that extract energy due to temperature
differences between two junctions (i.e., producing an electrical
current due to the difference between hot and cold environments)
using the well-known Peltier-Seebeck effect. Alternatively, the
technology can be based on a less refined approach, which uses the
junctions between two dissimilar metals as the regions at which the
hot and cold temperatures are applied to produce the voltage. While
the difference between normal human body temperature and the
ambient surrounding temperature is often only of few degrees, and
such minor temperature differences enable relatively little
electric power to be generated (and at voltages on the order of
only about 200 mV), the smart eyewear disclosed herein does not
require voltage from the voltage source except during switching
between states, and over time, sufficient energy can be collected
and stored to charge a rechargeable battery or to charge a
capacitor that is the actual source of the voltage applied to the
EC polymer material.
FIG. 10 schematically illustrates smart eyewear 74, which includes
support member 52, at least one pixelated one smart lens 76,
voltage source 56 operatively coupled to each smart lens, a
controller 62c (operatively coupled to the voltage source and each
pixel in the pixelated smart lens), and user interface 58
(operatively coupled to the controller). The incorporation of a
controller and a pixelated smart lens enables the smart eyewear to
support increasingly complicated and/or more versatile
functionality, as individual pixels in the smart lens can be
individually controlled.
For example, only pixels in certain portions (such as the upper
portion) of the smart lens can be switched to the tinted states
under certain conditions. In a more complicated smart lens,
different pixels can be implemented using a different color EC
polymer, and by selectively varying the state of individual pixels,
the tint or shade of the smart lens can be varied as desired (for
example, a user could switch from green tinted sunglasses, to brown
tinted, to yellow tinted, etc., depending on the types of EC
polymers employed). As red, blue, and green EC polymers have been
developed, a large number of colors and shades can be
supported.
If the individual pixels are made sufficiently small, it would be
possible to display text or even images on the smart lens by
controlling the transmittance of selected pixels to define the
image of letters comprising text.
In such a pixelated display, the plurality of individually
addressable pixels are preferably arranged in a grid format on the
smart lens. Each pixel is a laminated EC device such as the
laminated smart lens discussed above. By applying a voltage to each
pixel individually, selective tinting can be achieved, pixel by
pixel. The laminated EC devices described above are fabricated in a
digital (pixel) array, whose size are typically in the range from
0.5-50 microns across.
It should be noted that while the empirical embodiment was
fabricated using PPropOT-Me.sub.2 as the only EC polymer in the
smart lens, other EC polymers can be used to produce a smart lens.
Furthermore, in addition to the single layer EC polymer (i.e., a
single cathodic or anodic EC polymer) design, it will be recognized
that smart lenses can be fabricated using multiple layers of EC
polymers (such as a design that includes both an anodic EC polymer
and a cathodic EC polymer), if desired. Such designs may be
particularly well suited to smart lenses intended primarily for use
in very bright light environments, since the use of multiple layers
of EC polymers offers the ability to further reduce transmittance
of the smart lens.
FIGS. 11 and 12 schematically illustrate a pair of smart glasses
100, which as shown, incorporates a plurality of the elements
disclosed with respect to FIGS. 6-10. Thus, smart glasses 100 are
intended to provide an example of how such elements can be
integrated in a pair of smart glasses. It should be recognized that
elements such as sensors, energy harvesting elements, and
controllers are not required, and not all smart glasses encompassed
by the disclosure provided herein need incorporate such elements
(in other words, different embodiments could include different
combinations of the elements discussed above with respect to FIGS.
6-10).
Smart glasses 100 include support member 52, a pair of smart lenses
54 (noting that a single, larger smart lens extending over a
greater portion of smart glasses 100 could have been employed),
rechargeable battery 72, which is operatively coupled to each smart
lens (note that the electrical conductors coupling specific
elements together have not been specifically shown, and that if
desired, each smart lens could be powered by a separate battery),
user interface 58, sensor 66, energy harvesting element 70, and
controller 62b (operatively coupled to the rechargeable battery,
the user interface, the sensor, and the energy harvesting
element--although the conductors have not been shown). Further,
note that depending on the specific combination of elements
employed in smart glasses 100, other of controllers 62, 62a, and
62c might be beneficially employed. Each of the controller, sensor,
battery, user interface, and energy harvesting element have been
incorporated into the frame (i.e., support member 52) in this
exemplary embodiment. For glasses having relatively larger
earpieces, incorporating such elements into the earpieces of the
frame will not be a challenge. While only a single energy
harvesting element is shown, it should be recognized that one or
more additional energy harvesting elements could be added to the
other earpiece, and to the frame proximate a user's brow. The
energy harvesting elements are desirably positioned proximate a
user's skin to bring one junction of the energy harvesting elements
into contact with the body temperature of the user.
Note that smart lenses 54 are shown as being generally circular in
shape, although it should be recognized that many different form
factors can be employed, even curved form factors (where a flexible
polymer substrate is used in place of the ITO glass substrate,
generally as discussed above). Each smart lens 54 is divided into
an upper portion 54a and a lower portion 54b (noting that such
division is exemplary to this embodiment, and not all embodiments
encompassed herein will include such a division). In some
embodiments, only upper portion 54a includes an EC polymer that can
be manipulated to switch between a first state and a second state,
where the transmittance of the lens is greater in the first state.
In other embodiments, both the upper and lower portions include an
EC polymer, such that the upper and lower portions can be
individually controlled (for example, so that the upper portion can
be activated without also activating the lower portion). The upper
and lower portions can be implemented using the same EC polymer, or
different EC polymers. If different EC polymers are used for the
different portions, it will likely be preferable to use an EC
polymer exhibiting less total transmittance in the second state for
the upper portion.
FIG. 13 schematically illustrates a pair of exemplary smart glasses
102, which as shown, incorporates a plurality of the elements
disclosed with respect to FIGS. 6-10. Again, smart glasses 102 are
intended to provide an example of how such elements can be
integrated in a pair of smart glasses. It should be recognized that
elements such as sensors and energy harvesting elements are not
required, and as has been indicated, not all smart glasses
encompassed by the disclosure provided herein will include such
elements.
Smart glasses 102 include a support member 52a (such as a wire
frame, which is less suitable for incorporating elements such as a
battery or controller therein), a pair of pixelated smart lenses 76
(noting that a single, larger smart lens extending over a greater
portion of smart glasses 102 could have been employed instead),
rechargeable battery 72 operatively coupled to each smart lens
(noting that the electrical conductors coupling specific elements
together have not been specifically shown), user interface 58,
sensor 66, a plurality of energy harvesting elements 70a-70d, and
controller 62c (operatively coupled to the rechargeable battery,
the user interface, the sensor, the energy harvesting element, and
each pixel in the pixelated smart lenses; although the conductors
have not been shown). Further, note that depending on the specific
combination of elements employed in smart glasses 102, other of
controllers 62, 62a, and 62b might be beneficially employed. Note
that the user interface is included on support member 52a, while
the controller and battery have been moved to different portions of
the eyewear, as discussed below.
While a plurality of energy harvesting elements 70a-70d are shown,
it should be recognized that the relative position and number of
such elements is intended to be exemplary, and not limiting. Where
the energy harvesting elements rely on a user's body heat and the
differential between the body temperature and ambient temperature
to produce the voltage, the following portions of the smart glasses
can beneficially incorporate such energy harvesting elements:
portions of the support member/earpieces that engage the ears of a
user (see energy harvesting element 70a), portions of the support
member/earpieces that contact the sides of a user's head (see
energy harvesting element 70b), portions of the support
member/frame that contact a user's brow (see energy harvesting
element 70c), and portions of the support member (i.e., nose pieces
80) that contact a user's nose (see energy harvesting elements
70d).
As noted above, the form factor of support member 52a is such that
the battery and controller will not readily fit in the portion of
the earpieces extending along side the head of a user, as in smart
glasses 100 of FIGS. 11 and 12. Instead, those elements have been
moved to one of two different locations. In a first exemplary
embodiment, a portion 82 of support member 52a proximate a hinge 86
extends beyond the elongate earpiece, to provide space for the
controller and battery 72. Some sport sunglasses (particularly
those popular for winter sports, such as skiing) include a flexible
sun shield disposed proximate portion 82, to prevent light from
entering the sides of the glasses. Thus, the battery and controller
could be incorporated into such a flexible sun shield, and hidden
from casual view. If desired, a more rigid sun shield could also be
implemented, to similarly support the battery and controller. It
should also be noted that in many types of goggles, there is a
relatively large volume proximate portion 82 that can be used to
accommodate the controller and battery.
In a second exemplary embodiment, a portion 84 of support member
52a that engages a user's ear can be enlarged sufficiently to
accommodate the controller and battery 72, which enables the
balance of the support structure to be implemented using relatively
thin elements common in wire frame glasses. In some embodiments,
only a single earpiece includes such an enlarged portion 84, while
in other embodiments both earpieces includes an enlarged portion.
Where both earpieces include an enlarged portion, one earpiece can
include a portion 84 housing the controller, while the other
portion 84 can include the battery, thus both enlarged portions can
be smaller than if a single enlarged portion includes both of these
components. Regardless of whether one or two portions 84 are
implemented, the portion(s) can also include an energy harvesting
element as well, if desired. Further, the user interface can be
included in portion 84, if the balance of the support structure
does not provide sufficient space for including such an
element.
Referring once again to hinge 86, it should be noted that where
elements such as the battery and processor are disposed in the
earpieces, some conductor must pass near the hinge to reach the
smart lenses. Flexible conductors, particularly flexible tapes or
woven strand leads, can be used to provide conductivity and
flexibility.
FIG. 14 schematically illustrates a full face helmet 112 being worn
by a user 110, in which a smart lens 114 has been included. It
should be recognized that the concepts disclosed herein can also be
used in connection with partial face helmets, thus, the specific
form factor of the helmet is not important to this technology.
Helmets are used in sports (particularly football), by
motorcyclists and cyclists, in racing, in skydiving, by military
pilots, by astronauts, and by riot police (noting that such a list
is exemplary, and not limiting). The concepts disclosed herein can
be used to produce smart helmets for such activities and many
others. Significantly, helmets provide a much larger support member
than do the frames of a pair of glasses, and incorporating elements
such as energy harvesting members, processors, sensors, and
batteries into the form factor of a helmet will be simple. Of the
various embodiments disclosed above, it should be noted that
including a sensor and controller configured to automatically
adjust the transmittance of the smart lens in a smart helmet may be
of particular interest in military aviation and aerospace
applications, since pilots and astronauts generally do not have
hands that can be freed to adjust smart lens transmittance
manually, and the wearers of such helmets are often exposed to wide
variations of ambient light intensity.
FIG. 15 schematically illustrates a user 120 wearing a pair of
goggles 122 in which a smart lens 124 has been included. Goggles
are used in sports (particularly skiing), by motorcyclists and
cyclists, in racing, and in skydiving (noting that such a list is
exemplary, and not limiting). The concepts disclosed herein can
readily be used to produce smart goggles for such activities.
It should be recognized that several factors are involved in
achieving variable transmittance with the smart lens designs
disclosed herein. Variable transmittance can be achieved by
applying different electrical potentials to the smart lens. For
example, applying relatively larger potentials will result in
relatively greater tint saturations, up until the minimum
transmittance value is obtained. Thus, a relatively small applied
potential (such as about -0.2V) will yield a relatively light tint
and relatively greater transmittance, a relatively moderate applied
potential (such as about -0.6V) will yield a relatively moderate
tint and relatively less transmittance, and a relatively large
applied potential (such as about -1.5V) will yield a relatively
deep tint and relatively less transmittance as compared to the
lower applied potentials. In addition to the applied voltage, the
thickness of the EC polymer layer will also affect the light
transmittance range. For example, a relatively thicker film layer
might exhibit a variable transmittance ranging from about 45%-5%,
while a relatively thinner EC polymer film might exhibit a variable
transmittance ranging from about 70%-20%.
The smart lens designs disclosed herein can be incorporated into
prescription eyewear. Optical blanks are often provided to optical
outlets from optical laboratories. Such optical blanks are already
formed to close-to-exact size with different curves ground into the
front of the lens. Blanks with different curves are used for
specific optical prescriptions. The optical outlet then customizes
the rear of the optical blanks according to the wearers
prescription. In one embodiment, a smart lens 132 (i.e., the layers
described above to enable selective switching of one or more EC
polymers between the desired states) will be sandwiched between
glass or plastic optical blanks 130 (or between glass or plastic
substrates that are subsequently ground into optical blanks), as
schematically illustrated in FIG. 16A. In another embodiment, smart
lens 132 is deposited onto an upper surface of blank 130, as
schematically illustrated in FIG. 16B. When prescription glasses
are customized for a wearer, often only the lower (or inner)
surface of the blank needs to be modified (to adjust the power of
the lens). Thus, optical manufacturers can include the smart lens
layer in blanks provided to optical providers for customization for
a specific wearer. The smart lens can be added to an optical lens
as a fully functional layer (relatively thin smart lenses can be
achieved, and the use of flexible substrates in a smart lens will
enable the smart lens to match the curvature of an optical blank),
or an optical blank can be coated with an indium tin oxide layer,
such that the optical blank functions as one of the transparent
electrodes in the smart lens. For example, the upper surface of the
optical blank (after being ground to proper dimensions) can be
coated with indium tin oxide, and the EC polymer layer can be
deposited on the upper surface of the optical blank. The balance of
the smart lens can then be fabricated as discussed above in
connection with the description of FIGS. 1A and 1B. It should be
recognized that optical blanks used for prescription lenses are
available in many form factors, such that prescription smart lenses
can be incorporated into many different types and styles of
eyewear. Further, it should also be recognized that smart lens
layers can be sandwiched between glass or plastic substrates that
are subsequently ground and polished to achieve a prescription
lens.
It should be recognized that the graphs of FIGS. 2, 3, and 4 were
prepared using data from initial empirical studies. Later studies
have confirmed the soundness of the working principles disclosed
herein, and indicate even better switching and variable
transmittance performance is achievable than the preliminary
studies indicated. For example, subsequent studies achieved faster
switching times with the empirical device than are indicated in
FIG. 4, and that a more stable transmittance plateau is achieved in
the transparent state than is indicated in FIGS. 2 and 3.
Although the concepts disclosed herein have been described in
connection with the preferred form of practicing them and
modifications thereto, those of ordinary skill in the art will
understand that many other modifications can be made thereto within
the scope of the claims that follow. Accordingly, it is not
intended that the scope of these concepts in any way be limited by
the above description, but instead be determined entirely by
reference to the claims that follow.
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